Momentum Spectra in the Current Region of the Breit Frame in Deep Inelastic Scattering at HERA

The production of charged particles has been measured in deep inelastic scattering (DIS) with the ZEUS detector. The evolution of the moments of the scaled momenta distributions in $Q^2$ and $x$ has been investigated in the current fragmentation region of the Breit frame. The results in the current region are compared to $e^+e^-$ data and QCD analytical calculations. The results are consistent with the universality of single-particle spectra in DIS and $e^+e^-$ annihilation at high $Q^2.$ The results at low $Q^2$ disagree with analytical calculations based on the modified leading log approximation (MLLA) and local parton hadron duality (LPHD).Comment: 3 pages. 1 postscript figure + 1 postscript preprint logo + 1 LaTeX file + 1 style fil

Exploration of transitional life events in individuals with Friedreich ataxia: Implications for genetic counseling

<p>Abstract</p> <p>Background</p> <p>Human development is a process of change, adaptation and growth. Throughout this process, transitional events mark important points in time when one's life course is significantly altered. This study captures transitional life events brought about or altered by Friedreich ataxia, a progressive chronic illness leading to disability, and the impact of these events on an affected individual's life course.</p> <p>Methods</p> <p>Forty-two adults with Friedreich ataxia (18-65y) were interviewed regarding their perceptions of transitional life events. Data from the interviews were coded and analyzed thematically using an iterative process.</p> <p>Results</p> <p>Identified transitions were either a direct outcome of Friedreich ataxia, or a developmental event altered by having the condition. Specifically, an awareness of symptoms, fear of falling and changes in mobility status were the most salient themes from the experience of living with Friedreich ataxia. Developmental events primarily influenced by the condition were one's relationships and life's work.</p> <p>Conclusions</p> <p>Friedreich ataxia increased the complexity and magnitude of transitional events for study participants. Transitional events commonly represented significant loss and presented challenges to self-esteem and identity. Findings from this study help alert professionals of potentially challenging times in patients' lives, which are influenced by chronic illness or disability. Implications for developmental counseling approaches are suggested for genetic counseling.</p> <p>Background</p> <p>Human development can be described in terms of key transitional events, or significant times of change. Transitional events initiate shifts in the meaning or direction of life and require the individual to develop skills or utilize coping strategies to adapt to a novel situation <abbrgrp><abbr bid="B1">1</abbr><abbr bid="B2">2</abbr></abbrgrp>. A successful transition has been defined as the development of a sense of mastery over the changed event <abbrgrp><abbr bid="B3">3</abbr></abbrgrp>.</p> <p>Transitions can be influenced by a variety of factors including one's stage of development, such as graduation from high school, historical events, including war, and idiosyncratic factors, such as health status <abbrgrp><abbr bid="B4">4</abbr><abbr bid="B5">5</abbr></abbrgrp>. Of particular interest in the present study are transitional life events, brought about or altered by progressive chronic illness and disability, and the impact of these events on the lives of affected individuals.</p> <p>It has been recognized that the clinical characteristics of a chronic illness or disability may alter the course and timing of many developmentally-related transitional events <abbrgrp><abbr bid="B6">6</abbr></abbrgrp>. For example, conditions associated with a shortened lifespan may cause an individual to pursue a career with a shorter course of training <abbrgrp><abbr bid="B6">6</abbr></abbrgrp>. Specific medical manifestations may also promote a lifestyle incongruent with developmental needs <abbrgrp><abbr bid="B6">6</abbr><abbr bid="B7">7</abbr></abbrgrp>. For example, an adolescent with a disability may have difficulty achieving autonomy because of his/her physical dependence on others.</p> <p>In addition to the aforementioned effects of chronic illness and disability on developmentally-related transitional events, a growing body of literature has described disease-related transitional events: those changes that are a direct result of chronic illness and disability. Diagnosis has received attention as being a key disease-related transitional event <abbrgrp><abbr bid="B8">8</abbr><abbr bid="B9">9</abbr></abbrgrp>. Studies have also noted other disease transitions related to illness trajectory <abbrgrp><abbr bid="B10">10</abbr></abbrgrp>, as the clinical features of the disease may require the individual to make specific adaptations. Disease-related events have also been described in terms of accompanying psychological processes, such as one's awareness of differences brought about by illness <abbrgrp><abbr bid="B11">11</abbr></abbrgrp>.</p> <p>While disease-related events are seemingly significant, the patient's perception of the events is varied. Some events may be perceived as positive experiences for the individual. For example, a diagnosis may end years of uncertainty. Some individuals may perceive these transitional events as insignificant, as they have accommodated to the continual change brought about by a chronic disease <abbrgrp><abbr bid="B12">12</abbr><abbr bid="B13">13</abbr></abbrgrp>.</p> <p>The aforementioned impact of disability and chronic illness on transitional events may create psychological stress. Developed by Lazarus and Folkman, the Transitional Model of Stress and Coping describes the process of adaptation to a health condition <abbrgrp><abbr bid="B14">14</abbr></abbrgrp>. This model purports that individuals first appraise a stressor and then utilize a variety of coping strategies in order to meet the stressor's demands <abbrgrp><abbr bid="B14">14</abbr></abbrgrp>. Thus, in the context of chronic illness, the ability of the individual to cope successfully with the stress of a health threat contributes to the process of overall adaptation to the condition.</p> <p>The process of adaptation can be more complex when the chronic illness or disability is progressive. Each transition brought about or altered by the disability may also represent additional loss, including the loss of future plans, freedom in social life and the ability to participate in hobbies <abbrgrp><abbr bid="B15">15</abbr></abbrgrp>. These losses may be accompanied by grief, uncertainty, and a continual need for adaptation <abbrgrp><abbr bid="B16">16</abbr><abbr bid="B17">17</abbr></abbrgrp>.</p> <p>Friedreich ataxia (FRDA) is one example of a progressive disorder, leading to adolescent and adult onset disability. To better understand patients' perceptions of key transitional events and the factors perceived to facilitate progression through these events, individuals with FRDA were interviewed.</p> <p>FRDA is a rare, progressive, neurodegenerative disorder affecting approximately one in 30,000 people in the United States <abbrgrp><abbr bid="B18">18</abbr></abbrgrp>. It equally affects both men and women. Individuals with FRDA experience progressive muscle weakness and loss of coordination in the arms and legs. For most patients, ataxia leads to motor incapacitation and full-time use of a wheelchair, commonly by the late teens or early twenties. Other complications such as vision and hearing impairment, dysarthria, scoliosis, diabetes mellitus and hypertrophic cardiomyopathy may occur <abbrgrp><abbr bid="B19">19</abbr><abbr bid="B20">20</abbr></abbrgrp>. Cardiomyopathy and respiratory difficulties often lead to premature death at an average age of 37 years <abbrgrp><abbr bid="B21">21</abbr></abbrgrp>. Currently, there are no treatments or cures for FRDA. Little is known about the specific psychological or psychosocial effects of the condition.</p> <p>FRDA is an autosomal recessive condition. The typical molecular basis of Friedreich ataxia is the expansion of a GAA trinucleotide repeat in both copies of the <it>FXN </it>gene <abbrgrp><abbr bid="B22">22</abbr></abbrgrp>. Age of onset usually occurs in late childhood or early adolescence. However, the availability of genetic testing has identified affected individuals with an adult form of the condition. This late-onset form is thought to represent approximately 10-15% of the total FRDA population <abbrgrp><abbr bid="B23">23</abbr></abbrgrp>.</p> <p>Health care providers of individuals with progressive, neurodegenerative disorders can help facilitate their patients' progression through transitional events. Data suggest that improvements should be made in the care of these individuals. Shaw et al. <abbrgrp><abbr bid="B24">24</abbr></abbrgrp> found that individualized care that helps to prepare patients for transition is beneficial. Beisecker et al. <abbrgrp><abbr bid="B25">25</abbr></abbrgrp> found that patients desire not only physical care from their providers, but also emotional and psychosocial support.</p> <p>Genetic counselors have an important opportunity to help patients with neuromuscular disorders progress through transitional events, as several of these conditions have a genetic etiology. Genetic counselors in pediatric and adult settings often develop long-term relationships with patients, due to follow-up care. This extended relationship is becoming increasingly common as genetic counselors move into various medical sub-specialties, such as neurology, ophthalmology, oncology and cardiology.</p> <p>The role of the genetic counselor in addressing the psychosocial needs of patients has been advocated, but rarely framed in the context of developmental events <abbrgrp><abbr bid="B26">26</abbr></abbrgrp>. Data suggest that patients may not expect a genetic counselor to address psychosocial needs <abbrgrp><abbr bid="B27">27</abbr></abbrgrp>. In a survey of genetic counseling patients, Wertz <abbrgrp><abbr bid="B28">28</abbr></abbrgrp> found a majority of respondents understood genetic conditions to have a moderate to serious effect on family life and finances, while almost half perceived there to be an effect on the spouse, quality of life, and the relationship between home and work. However, these topics were reportedly not discussed within genetic counseling sessions <abbrgrp><abbr bid="B27">27</abbr><abbr bid="B28">28</abbr></abbrgrp>. Overall, there is limited information about the experiences of transitional life events in FRDA, as well as a lack of recommendations for genetic counselors and other health care providers to assist patients through these events.</p> <p>Our study investigated perceptions of patients with Friedreich ataxia to 1) identify key transitional events and specific needs associated with events; 2) describe perception of factors to facilitate progression through the identified events; and 3) explore the actual or potential role of the health care provider in facilitating adaptation to the identified events. Data were used to make suggestions for developmental genetic counseling approaches in the context of ongoing care of clients with hereditary, progressive, neurodegenerative conditions.</p

Thin disc, Thick Disc and Halo in a Simulated Galaxy

Within a cosmological hydrodynamical simulation, we form a disc galaxy with sub- components which can be assigned to a thin stellar disc, thick disk, and a low mass stellar halo via a chemical decomposition. The thin and thick disc populations so selected are distinct in their ages, kinematics, and metallicities. Thin disc stars are young (<6.6 Gyr), possess low velocity dispersion ({\sigma}U,V,W = 41, 31, 25 km/s), high [Fe/H], and low [O/Fe]. The thick disc stars are old (6.6<age<9.8 Gyrs), lag the thin disc by \sim21 km/s, possess higher velocity dispersion ({\sigma}U,V,W = 49, 44, 35 km/s), relatively low [Fe/H] and high [O/Fe]. The halo component comprises less than 4% of stars in the "solar annulus" of the simulation, has low metallicity, a velocity ellipsoid defined by ({\sigma}U,V,W = 62, 46, 45 km/s) and is formed primarily in-situ during an early merger epoch. Gas-rich mergers during this epoch play a major role in fuelling the formation of the old disc stars (the thick disc). This is consistent with studies which show that cold accretion is the main source of a disc galaxy's baryons. Our simulation initially forms a relatively short (scalelength \sim1.7 kpc at z=1) and kinematically hot disc, primarily from gas accreted during the galaxy's merger epoch. Far from being a competing formation scenario, migration is crucial for reconciling the short, hot, discs which form at high redshift in {\Lambda}CDM, with the properties of the thick disc at z=0. The thick disc, as defined by its abundances maintains its relatively short scale-length at z = 0 (2.31 kpc) compared with the total disc scale-length of 2.73 kpc. The inside-out nature of disc growth is imprinted the evolution of abundances such that the metal poor {\alpha}-young population has a larger scale-length (4.07 kpc) than the more chemically evolved metal rich {\alpha}-young population (2.74 kpc).Comment: Submitted to MNRAS. This version after helpful referee comments. Comments welcome to [email protected]

A Satellite-Based Multi-Pollutant Index of Global Air Quality

Air pollution is a major health hazard that is responsible formillions of annual excess deaths worldwide. Simpleindicators are useful for comparative studies and to asses strends over time. The development of global indicators hasbeen impeded by the lack of ground-based observations in vast regions of the world. Recognition is growing of the need for amultipollutant approach to air quality to better represent human exposure. Here we introduce the prospect of amultipollutant air quality indicator based on observations from satellite remote sensing

Primary care consultations and costs among HIV-positive individulas in UK primary care 1995-2005: a cohort study

Objectives: To investigate the role of primary care in the management of HIV and estimate primary care-associated costs at a time of rising prevalence. Methods: Retrospective cohort study between 1995 and 2005, using data from general practices contributing data to the UK General Practice Research Database. Patterns of consultation and morbidity and associated consultation costs were analysed among all practice-registered patients for whom HIV-positive status was recorded in the general practice record. Results: 348 practices yielded 5504 person-years (py) of follow-up for known HIV-positive patients, who consult in general practice frequently (4.2 consultations/py by men, 5.2 consultations/py by women, in 2005) for a range of conditions. Consultation rates declined in the late 1990s from 5.0 and 7.3 consultations/py in 1995 in men and women, respectively, converging to rates similar to the wider population. Costs of consultation (general practitioner and nurse, combined) reflect these changes, at £100.27 for male patients and £117.08 for female patients in 2005. Approximately one in six medications prescribed in primary care for HIV-positive individuals has the potential for major interaction with antiretroviral medications. Conclusion: HIV-positive individuals known in general practice now consult on a similar scale to the wider population. Further research should be undertaken to explore how primary care can best contribute to improving the health outcomes of this group with chronic illness. Their substantial use of primary care suggests there may be potential to develop effective integrated care pathways

Making Galaxies in a Cosmological Context: The Need for Early Stellar Feedback

We introduce the Making Galaxies in a Cosmological Context (MaGICC) program of smoothed particle hydrodynamics (SPH) simulations. We describe a parameter study of galaxy formation simulations of an L* galaxy that uses early stellar feedback combined with supernova feedback to match the stellar mass--halo mass relationship. While supernova feedback alone can reduce star formation enough to match the stellar mass--halo mass relationship, the galaxy forms too many stars before z=2 to match the evolution seen using abundance matching. Our early stellar feedback is purely thermal and thus operates like a UV ionization source as well as providing some additional pressure from the radiation of massive, young stars. The early feedback heats gas to >10^6 K before cooling to 10^4 K. The pressure from this hot gas creates a more extended disk and prevents more star formation prior to z=1 than supernovae feedback alone. The resulting disk galaxy has a flat rotation curve, an exponential surface brightness profile, and matches a wide range of disk scaling relationships. The disk forms from the inside-out with an increasing exponential scale length as the galaxy evolves. Overall, early stellar feedback helps to simulate galaxies that match observational results at low and high redshifts.Comment: 13 pages, 14 figures, accepted MNRAS, movies at http://www.mpia.de/~stinson/magic

Late Miocene to early Pliocene biofacies of Wanganui and Taranaki Basins, New Zealand: Applications to paleoenvironmental and sequence stratigraphic analysis

The Matemateaonga Formation is late Miocene to early Pliocene (upper Tongaporutuan to lower Opoitian New Zealand Stages) in age. The formation comprises chiefly shellbeds, siliciclastic sandstone, and siltstone units and to a lesser extent non-marine and shallow marine conglomerate and rare paralic facies. The Matemateaonga Formation accumulated chiefly in shelf paleoenvironments during basement onlap and progradation of a late Miocene to early Pliocene continental margin wedge in the Wanganui and Taranaki Basins. The formation is strongly cyclothemic, being characterised by recurrent vertically stacked facies successions, bounded by sequence boundaries. These facies accumulated in a range of shoreface to mid-outer shelf paleoenvironments during conditions of successively oscillating sea level. This sequential repetition of facies and the biofacies they enclose are the result of sixth-order glacio-eustatic cyclicity. Macrofaunal associations have been identified from statistical analysis of macrofossil occurrences collected from multiple sequences. Each association is restricted to particular lithofacies and stratal positions and shows a consistent order and/or position within the sequences. This pattern of temporal paleoecologic change appears to be the result of lateral, facies-related shifting of broad biofacies belts, or habitat-tracking, in response to fluctuations of relative sea level, sediment flux, and other associated paleoenvironmental variables. The associations also show strong similarity in terms of their generic composition to biofacies identified in younger sedimentary strata and the modern marine benthic environment in New Zealand

Elastic constants of nematic liquid crystals of uniaxial symmetry

We study in detail the influence of molecular interactions on the Frank elastic constants of uniaxial nematic liquid crystals composed of molecules of cylindrical symmetry. A brief summary of the status of theoretical development for the elastic constants of nematics is presented. Considering a pair potential having both repulsive and attractive parts numerical calculations are reported for three systems MBBA, PAA and 8OCB. For these systems the length-to-width ratio ${x_0}$ is estimated from the experimentally proposed structure of the molecules. The repulsive interaction is represented by a repulsion between hard ellipsoids of revolution (HER) and the attractive potential is represented by the quadrupole and dispersion interactions. From the numerical results we observe that in the density range of nematics the contribution of the quadrupole and dispersion interactions are small as compared to the repulsive HER interaction. The inclusion of attractive interaction reduces the values of elastic constants ratios. The temperature variation of elastic constants ratios are reported and compared with the experimental values. A reasonably good agreement between theory and experiment is observed

Deconfinement Transition and Bound States in Frustrated Heisenberg Chains: Regimes of Forced and Spontaneous Dimerization

We use recently developed strong-coupling expansion methods to study the two-particle spectra for the frustrated alternating Heisenberg model, consisting of an alternating nearest neighbor antiferromagnetic exchange and a uniform second neighbor antiferromagnetic exchange. Starting from the limit of weakly coupled dimers, we develop high order series expansions for the effective Hamiltonian in the two-particle subspace. In the limit of a strong applied dimerization, we calculate accurately various properties of singlet and triplet bound states and quintet antibound states. We also develop series expansions for bound state energies in various sectors, which can be extrapolated using standard methods to cases where the external bond-alternation goes to zero. We study the properties of singlet and triplet bound states in the latter limit and suggest a crucial role for the bound states in the unbinding of triplets and deconfinement of spin-half excitations.Comment: 17 figures, revte